Method of line reproduction



June 8,1943. B, RUDNlCK METHOD oF LINE REPRODUCTION Filed May 21, 194:1v'2 sheets-sheet. 1

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- l METHOD OF yLINE- REPRODUCTION l Film1 May 21.` 1941;- y i 2sheets-shale?. 2

MASK/NG MATER/AL (tm base n .(a/ammam base) v A57/c @Ack/Ns s//ffrINVENTOR ATTORNEY i Patented June 8, 1943 o .Unirse sr Mn'rnon orLrNEnErRonUoTIoN Benjamin Rudnick,

Huntington, N. Y., assigner l to Republic Aviation Corporation,Farmingdale, N. Y., a corporation of Delaware Application May 21, 1941,serial No. 394,403

(oresv 6 Claims.

lThis invention relates to a lmethod of line reproduction by whichdesigns or other graphic characters or delineations may be transferredfrom one surface to anothed quickly, accurately and repeatedly.

More particularly the invention aims tol provide a method ofreproduction by which inscriptions, for example, line drawings,luminescently produced upon a surface may be transferred to anothersurface, which has previously been rendered light-sensitive bymomentarily placing the two surfaces in contact with each other to causeFigure 1 is a plan view of a pattern sheet having a drawing inscribedthereon;

Figure 2 is 'a cross-sectional view of the pattern sheet taken onttheline 2-2 of Figure 1, the coating layers being shown, for greaterclearness,

` somewhat exaggerated in thickness;

exposure of the sensitizedsurface by the luminesoent inscriptions.

One method may be advantageously carried out in the following manner: Astili backing r sheet or plate is' coated with 'a layer Vof `luminescentmaterial having an overcoating of opaque masking material, the layers ofluminescent'and masking materials constituting what, for convenience, Iterm a negative surface. `The copy sheet to which the design isto betransferredis coated with a film of light-sensitive emulsion so as toform what may be referred to as a positive surface. The drawing to bereproduced is made upon the negative surface by means of a-stylus orother pointed scratches through the overcoating of opaque maskingmaterial and uncovers the luminescent material. After presenting thenegative surface to abright light, either natural or artificial, toexcite the uncovered luminescentrnaterial, the treated surfaces aresuperimposed to allow'the light rays emitted by the uncoveredluminescent material to act upon the light-sensitive film. Finally thecopy sheet is developed and xed in lthe usual photographic solutions toreduce the exposed areas to visible metallic silver, leaving these areasblack and clear-cut, and corresponding exactly to the lines oftheoriginal drawing.

-The method is not limited to the reproduction Y of drawings upon sheetmaterial, and will indeed find great utility in machine and sheet metalshop kpractice in transferring mechanical layouts or templates as .theycomel from the drafting table `directly onto the work to be machined,metalsmithed or otherwise operated upon.

Another object` of my invention is to provide A means for practicingVthe foregoing method.-

Other objects and advantages will be apparent from the followingdetailed description of two preferredmodes of carrying out the method. yof my invention, reference being had to the annexed drawings in which:Figures 1 to 4 refer to the first mode;

instrument which cuts or Figure '3 is a cross-sectional view ofgEt-copyl sheet, the layers of coating material being-shwn exaggeratedinthickness; and

Figure 4-indicates sheets are arranged during their exposure. l

Figures 56 and 7 are views similar to Figures 2,'3, 4 respectively ofthe second mode: and

Figure 8 shows a different manner in which the sheets map be arrangedduring their exposure. v

In Figures 1 and 2 of the drawings is illustrat- A comprising a backingsheet to free it from dirt,V grease, or oiLfollowing which a thincoating of white paint 2, containing no klead compounds, is applied overthe surface.

Upon the coating of. white paint is deposited,

either by a spray-or a brush, a layer of a luminescent composition 3suspended-'in atransparent vehicle. For this luminescent composition I`the reaction productV resulting fromA igniting a mixture ofcalcium-carbonate and sul-- prefer to use phur togetherwith smallquantitiesfof bismuth or manganese salts, this reaction product beingsuspended in a vehicle of unpigmented nitrocellulose lacquer thinned toa suitable consistency. After allowing the luminescent composition/todry sothat it is no longer tacky butl rrn and hard, a thin coating ofopaque masking material 4 is evenly distributed over its surface,` ysoas to completelyl cover the luminescent layer,` This masking materialmay comprise af black lacquer such as is compatible with the' lacquervehicle containing the luminescent composition.

The layer of luminescent material overlain by the-coating of maskingmaterial constitutes a l upon' which,-after drying, a drawing 5 maybeinscribed by means of a stylus negative surface or other pointedinstrument, which cuts through the overcoating-fof masking material andbares the luminescent composition underneath. Be,-

cause of the fact that the masking material' adheres as an extremelythin coating to the luminescent composition, Vit may be readilypenetrated by the usual drafting instruments, such as a pen orA compassprovided with-a stylus point, and

Acalls for no materially different technique on the the manner inwhichthe cle carrying the luminescent by painting over,

vsummary,

l the pattern sheet with part of the draftsman from what isinvolved inthe preparation of the usual mechanical drawnitrocellulose vehiings..Since the translucent composition is superimposed .upon the whiteundercoating of paint 2, thev lines produced by the stylus stand outsharply and clean-cut against the black` background of the the draftsmanmake .out the drawing.

masking material.l Should a mistike in initially laying this may bereadily corrected and thus blacking out the incorrectly placed lineswith a black lacquer corresponding in composition to that of the maskingmaterial, the correct lines afterwards added when the lacquer has dried.

in a strong light, which may be either natural sunlight or artificiallight, for example ultraviolet light, the purpose ofwhich is to excitethe ent composition uncovered by the stylus sothatit gives oi!radiations in a dark room.

` Y Only a-few minutes is required for such excitation, following whichthe pattern sheet is ready for use as a master negative from whichreproductions of the-drawing may be photographically transferred to copysheets. one of suchV copy sheets, designated B,- being shown incross-section in Figure 3. 'i

copy sheet B offmetal, fabric, pape., glass, wood, or any other suitablematerial, or it may vconstitute the actual work to One face of thebacking sheet synthetic plastic,

Y iscleaned. Acosting of priming-.material 'l is then painted or sprayedover the cleaned surface. the primer serving both as a ller for closingthe pores of the material composing the backing sheet,v and as a.protective shield between the backing sheet and the emulsion whichissubsequently applied thereto, yand which otherwise being Thethus-prepared pattern 'sheet is now placed comprises a backingsheet- 63,321,249 n l emitted by the uncovered luminescent'composition actphotographically upon the light-sensitive emulsion and cause the silversalts to be sumciently aifected usually minutes. removed and fixingsolutions in a manner which is well- The thus-exposed copy sheet isnally known to thephotographic art, and then washed and dried. Becausethe negative surface retains dts luminescence for a considerable time, agreat of copies of the drawing may be reproduced therefrom in a singledark room operation;` -and when its luminosity becomes spent it can berestored number by again presenting it to a strong light. The drawingreproduced upon the copy sheet exhibits and restful to the eyes. Ifdesired, however, bleached out to reveal the color of the backing sheetl, by immersing the solution of ammonium hydroxide; or the copy sheetmay be rendered transparent if glass or a transparentplastic is employedas the backing be operated upon.

steel. both of its faces, as well as its edges,.will l' be covered withthe primer to. avoid contamination of thechemicals employed in thesubsequent developingoperation. v

I'he copyv sheet is next placed in a dark room illuminated, for example,by a ruby safelight of the type well known to photography; thetemperature is maintained substantially Yconstant and an emulsion l,consistingJorexample. or a light-sensitive material, suchk asusilvernitrate suspended in a gelatinous vehicle, is melted and applied as aillm in any suitable manner giving aneven thickness, though I prefertoapplyit with a Vlow-pressure spray gun smoothly and uniformly over theprimer coating. The thus-prepared sheet is then passed through achilling chamber lcausing, the emulsionto jell, after whichitisplacedinadryer.y Y

The prepared copy sheet B may be used as soon in engagement with thetreated face of the pattern sheet to insure absolute contacttherebetween., Under such conditions, the light rays or it may be storedaway in a lightmaterial. y

If an aluminum of the copy sheet, can be applied directly on the metalby first cleaning the surface in a sodium hydroxide solution and thendipping ina diluted nitric acid bath to neutralize the caustic action.

'I'he method is particularLv useful for making templates. The drawing `lindicatedin represents a cross-section contour of an aircraft wingpanel. By transferring this drawing to a sheet of metal or other rigidmaterial in the manner already described, and then cutting alongthelines of the reproduced drawing, a' template corresponding to thecontour of the original drawing is obtained.

Manifestly the procedure described above is susceptible of modification.While I have found 4that a luminescent composition incorporating thereaction product of burned calcium carbonate and sulphur, asabove-described, gives excellent results besides being comparativelyinexpensive to produce. nevertheless other compositionsxm'ay be alioy isused as the backing Y advantageously employed such', for example, as

its treated face held firmly the phosphorus compounds.` The coatingofwhite paint 2 upon Vthe pattern sheet may be omitted if desired, andthe ,luminescent material applied directly to the backing sheet i. 'YHowever, the

y presence of this white substratum advantageously affects the resultsobtained. particularly in those to reflect transmitted light. y Y Y ,v

In' some cases.A also,l it may be desirable to apply a. `thin coating ofa solution, such as potassiumchrome-alum dissolvedin a nve percentsolution of gelatine. over the primer 1 upon the copy sheetV an olddrawing-1`nay be inscribed upon therenewed surface,"theprocedure beingotherwise the same as that described above. Y

' Another method of preparing a negative which can be used toreproduceonto the same lightin about one and one-half to two" andtreated withtheusual developing v black, sharply-defined lines againstthe olive-green vbackground of the vprimer coating. which is pleasingthe olive-green color may be` copy sheet in a dilute Vthelight-sensitive emulsionv Figure 1 sensitive coated copy sheets 'as areused in the luminous process may `be carried out in the following manner(Figures to 8): A clear plastic Vsheet .01 to .015 thick is coated withan opaque masking material consistingv of two separatel layers lo, ii ofa metallic lacquer. These layers of metallic lacquer are so applied thatthey can be scribed on or cut away, without scratching or cutting intothe plastic backing sheet 9. 'The first coating lo is prepared by mixinga quantity of iinely ground aluminum powder in nitro-cellulose lacquerto form a thick paste. This is thinned with a mixture of solvents to asuitable consistency and is applied to the surface of the plastic sheet9. This coating Il when dry renders the plastic material 9 opaque butcan read- .ily be removed with a few strokes of a stiff brush. Thematerial for the second coating- Ii is prepared by mixing a quantity ofmetallic powder, which consists mainly of tin, to a greater amount ofnitro-cellulose lacquer than was used in the rst coating iii. To this isadded enough solvents to thin to the desired consistency and this isapplied over the iirst layer lli. Upon drying,

the second coating ii acts as a binder for the;

first coating i0. The drawing to be reproduced (not shown) is drawn onthis surface byV means of a pointed instrument which cuts or removes 'ithe top layerV Il of masking material making it possible to brush outthe aluminum powder i0 underneath, covering the transparent plasticbacking 9. This is now used as a photographic negative C. It is placedin contact with the light-sensitive copy sheet 6, 1, s and exposed toartiiicial light for a predetermined time. These light rays pass throughthe transparent portions Seriali Y Y 2. A method oflinereproductionwhich com'- prises providing a backing member with anegative surface composed of a layer of a luminescent composition and acoating of opaque masking material overlying the luminescent layer,lprovidinga second backing member with alpositive surface composed of acoating of light-sensitive material, inscribing the negative layer soas' to uncover the luminescent composition, presenting the negativesurface to a bright light to cause ex citation' of the uncoveredluminescent composition, superimposing .the negative and positivesurfaces with exclusion oflight so as to expose the light-sensitivematerial to the uncovered luminescent composition, and photographicsllydeveloping the positive surface to remove the unexposed portions oflight-sensitivemateriah.

3. A method of reproducing layouts in me chanical manufacture which'comprises preparing a pattern sheet with a layer of .a luminescentcomposition, coating said layer with an opaque masking material.inscribing a layout upon sold maskinghcoating so as to uncover theunderiayer of luminescent composition, Providing o. iilm of ylight-sensitive material upon the work to be operated upon, presentingthe, pattern sheet' to s.. bright light to cause excitation of theuncovered luminescent compositiomsuperimpoaing the-pst-A Y tern sheet`upon the work so as to expose the f light-sensitive film totheuncovered luminescentv of the plastic negative, reacting on thelightsensitive salts of the copy sheet. The exposed copy sheet is thenprocessed in the usual photographic solutions. The resultingreproduction appears as a sharply deilned black line on a cleancontrasting background. An oustanding advantage in the use of theplastic negative is the fact that either a right hand or lefthandreproduction can be obtained accurately by merely placing the coatedsurface of the plastic negative C (to produce a copy in reverse oi' thedesign as drawn) I layouts, etc.

Manifestly various other modications in the foregoing methods may bemade by those skilled in the art without departing from the spirit of myinvention as deilned in the following claims. I claim:

l. A method' of line reproduction which comprises providing a Vbackingmember with a negative surface composed of a layer of a luminescentcomposition and 'a coating of opaque masking material overlying theluminescent layer, providing 'a second backing member with a positivesurface composed of a coating of light-sensitive material, inscribingthe negative layer so as to uncover the luminescent composition,superimposing the negative and positive surfaces so as to expose thelight-sensitive material to the uncovered luminescent composition, andphotographically developing the positive surface to remove composition,photographically developing Athe work surface to remove the unex-posedportions of the light-sensitive film, and utilising the thus reproducedlayout upon the work as a guide'for l the performance .of mechanicaloperations upon the work. 4. The method of line reproduction, whichcomprises: providing a backing member with s..

negative surface composed ofa nlm of a luminosi cent composition and acoating oi' opqlle masking material overlying the luminescentilluminscribing the designs to be reproducedonfsaid negative surface bylinearly removingjsaid masking material with a pointedinstrumentypresentl ing the negative surface thus inscribed to a brightlight to cause excitation ofthe uncovered portions of the luminescentnlm corresponding to said designs; providing a positive'surface, by.

Y coating the sheet on which the designs are to be Y reproduced with afilm of light-sensitive material; superimposing said negative andpositive surfaces, in the absence ot visible light, to expose theiight-sensitive maternal to the rays emitted br the uncovered portionsof the luminescent film: and photographically developing the positivesurv face in such manner as to remove the unexpo portions oflight-sensitive material.

5. A method of line reproduction which comprises -providing a supportingsheet with'a costing of luminescent material having an overlay ofopaqueA masking material, removing said masking material to`1mcover the'luminescent material throughout predetermined areas'in theform ofthedesign to be reproduced, arranging 'said-supporting sheet in superposedrelation with respect to a body having a surface lnlm of alight-sensitive material to expose said nlm to the rays'k emitted by theuncovered luminescent material, and photographically developing thebodyto remove the unexposed portionsof the iilxn.

6. A method of line reproduction which comprises providing a supportingsheet with a ing of luminescent material having an1 overlay theunexposed portions time' iights'ensitiverma; fr

4 j l .fzjannuo 'of opaqlernasking material, said mash' y ingmaterial-to uncover theluminescent material sensitive material to exposesaid 111m to the rays throughout predetermined areas inv the form ofemitted by the uncovered luminescent material. the design to bereproduced, presenting said sheet and photographically developing thebody to reto a bright light to ause'excitatlon ofthe un- 5 move theunexposed portions of the iilln.- covered luminescent material,arranging said f spect to a body having a surface nim of s,lightsupporting 'sheetin superposed relation with ree i l BENJAMINRUNICK.

